Exoplanets (NExSS)

The study of exoplanets – planets around other stars – is a relatively new field. The discovery of the first exoplanet around a star like our sun was made in 1995. Since the launch of NASA’s Kepler space telescope six years ago, more than 1,000 exoplanets have been found, with thousands of additional candidates waiting to be confirmed. Scientists are developing ways to confirm the habitability of these worlds and search for biosignatures, or signs of life.

The Exoplanets Research program conducts research to advance our knowledge and understanding of exoplanetary systems. Its objectives are the detection and characterization of exoplanets (including their surfaces, interiors, and atmospheres) and exoplanetary systems, including the determination of their compositions, dynamics, energetics, and chemical behaviors. This program element is shared between NASA’s Planetary Science Division (PSD) and the Astrophysics Division.

The Nexus for Exoplanet System Science (NExSS)

In 2015, NASA’s Astrobiology Program within the PSD formed NExSS, a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context – as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur and which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.

Many Worlds Blog

The Many Worlds Blog chronicles the search for evidence of life beyond Earth written by author/journalist Marc Kaufman. Many Worlds is supported by NASA’s Astrobiology Program and NExSS.

The NExSS Team

NExSS is led by Natalie Batalha of NASA’s Ames Research Center, Dawn Gelino of the NASA Exoplanet Science Institute (NExScI), and Anthony del Genio of NASA’s Goddard Institute for Space Studies. The NExSS project includes team members from 10 different universities and two research institutes.

The Living, Breathing PlanetLead: William B. Moore, Hampton University
Exploring the sources and sinks for volatiles on habitable worlds. The team will study how the loss of hydrogen and other atmospheric compounds to space has profoundly changed the chemistry and surface conditions of planets in the solar system and beyond. This research will help determine the past and present habitability of Mars and even Venus, and will form the basis for identifying habitable and eventually living planets around other stars.

The Virtual Planetary LaboratoryLead: Victoria Meadows, The NASA Astrobiology Institute’s Virtual Planetary Laboratory (VPL), based at the University of WashingtonVPL was founded in 2001 and is a heritage team of the NExSS network. This research group will combine expertise from Earth observations, Earth system science, planetary science, and astronomy to explore factors likely to affect the habitability of exoplanets, as well as the remote detectability of global signs of habitability and life.

Five additional teams were chosen from the Planetary Science Division portion of the Exoplanets Research Program (ExRP). Each brings a unique combination of expertise to understand the fundamental origins of exoplanetary systems, through laboratory, observational, and modeling studies.

The Planet-Forming Environment Close to Young StarsLead: Neal Turner, NASA’s Jet Propulsion Laboratory, California Institute of Technology
Working to understand why so many exoplanets orbit close to their stars. Were they born where we find them, or did they form farther out and spiral inward? The team will investigate how the gas and dust close to young stars interact with planets, using computer modeling to go beyond what can be imaged with today’s telescopes on the ground and in space.

Bulk Properties of Small Transiting Planets and Implications for their Formation Lead: Eric Ford, Penn State University
Striving to further understand planetary formation by investigating the bulk properties of small transiting planets and implications for their formation.

Extending Spitzer to the Ground: A Novel Technique for Probing Exoplanetary Atmospheres Lead: Jason Wright, Penn State University
Studying the atmospheres of giant planets that are transiting hot Jupiters with a novel, high-precision technique called diffuser-assisted photometry. This research aims to enable more detailed characterization of the temperatures, pressures, composition, and variability of exoplanet atmospheres.

Tidal Dynamics and Orbital Evolution of Terrestrial Class Exoplanets with Time-Varying Internal Melt Fractions Lead: Wade Henning, University of Maryland and NASA’s Goddard Space Flight Center
Studying tidal dynamics and orbital evolution of terrestrial class exoplanets. This effort will explore how intense tidal heating, such as the temporary creation of magma oceans, can actually save Earth-sized planets from being ejected during the orbital chaos of early solar systems.

Characterizing the Habitable Zone Planets of Kepler StarsLead: Debra Fischer, Yale University
Designing new spectrometers with the stability to reach Earth-detecting precision for nearby stars. The team will also make improvements to Planet Hunters, www.planethunters.org, a web interface that allows citizen scientists to search for transiting planets in the NASA Kepler public archive data. Citizen scientists have found more than 100 planets not previously detected; many of these planets are in the habitable zones of host stars.

Exploring Exoplanetary Exospheres: Extended Atmosphere Detection, Characterization, and Evolution in ExoplanetsLead: Adam Jensen, University of Nebraska-Kearney
Explore the existence and evolution of exospheres around exoplanets, the outer, ‘unbound’ portion of a planet’s atmosphere. This team previously made the first visible light detection of hydrogen absorption from an exoplanet’s exosphere, indicating a source of hot, excited hydrogen around the planet. The existence of such hydrogen can potentially tell us about the long-term evolution of a planet’s atmosphere, including the effects and interactions of stellar winds and planetary magnetic fields.

Forward and Inverse Modeling of Brown Dwarf AtmospheresLead: Jonathan Fortney, University of California, Santa Cruz
Investigating how novel statistical methods can be used to extract information from light which is emitted and reflected by planetary atmospheres, in order to understand their atmospheric temperatures and the abundance of molecules.

NExSS – NASA Postdoctoral Program (NPP)

The NASA Astrobiology Program element of the NPP provides opportunities for Ph.D. scientists and engineers of unusual promise and ability to perform research on problems largely of their own choosing, yet compatible with the research interests of the NASA Astrobiology Program.

Daniel Carrera
Advisors: Eric B. Ford (Pennsylvania State University and NExSS Group 1: Bulk Properties of Small Transiting Planets and Implications for their Formation) and members of the Virtual Planetary Laboratory NExSS team.
Topic: “Composition Of Small Transiting Planets”